Method of operating- saws



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FREDERICK T. ANDREWS, OF GEORGETOVYN, DISTRICT vOF COLUMBIA.

METHOD or orERATiNG sAws.

specificati@ of Letters Patent No. 10,538, dated Febmary 21, 1854.

To all whom t mayconcem Be it known that I, FREDERICK T. AN

DREws, of Georgetown, in the District of Columbia, have invented certain new andi useful Improvements in Sawmills; and I do hereby declare the following to be a full, clear, vand exact description thereof, reference being had to the accompanying drawings and to letters of reference marked thereon, in which- Figure l is a plan view of the mill; Fig. 2, a side elevation; Fig. 3, a transverse section on the line af: of Fig. l; Fig. 4, a Vertical longitudinal section on the line 0, o, of Fig. 1.

My invention has reference to that class of saw mills in which the vertical reciprocating saw is used, and it consists in communicating in a compact and convenient form and in 'a more uniform, gradual and eifective manner than has heretofore, been done, the usual advance movement of the saw during its downward action and receding motion during its upward stroke and whereby t-he saw is more perfectly freed from gum and saw-dust and performs a more regular and easy cut.

The main framing (A) of the mill, together with its ways (a) and the carriage (B) are constructed similar to the ordinary mill, therefore any minute description of them here is deemed unnecessary. On either side of this main frame, I erect t-wo uprights (C, CQ) having grooves on their inner sides, from the top downward, to receive a vertical sliding frame (D), to which are firmly attached two grooved or V shaped guides (c, 0,) at suitable distance apart, for the upper cross-head (d) of the saw to work between. At the lower ends of these guides, are bolted adjustable clamps (e), which are intended to steady the saw. Above and near to the timber to be cut, this frame (D) together with the guides and clamps, is raised or lowered to suit the thickness of the log to be cut, so that the clamps which steady the saw shall always be as near the log as convenient, and is thus operated by means of the roller (E) having cords or chains attaching it thereto, which are wound up or lowered out, by hand spikes, a ratchet lever, or other suitable means. To the main frame of the mill, below the level of the carriage, are also attached two grooved or V shaped guides (f, f,) to guide the vertical action of the lower cross-head (g) of 1: Vthe saw, to which cross-head the saw is attached by a rocking link (It). The upper end of said link is pinned to the saw, the Alower end is connected to the yend of the kdriving beam (F), andthe center of -it head, or it might perhaps more conveniently be made with trunnions fitted into brasses Y which slide between the guides (f, f). Thus it will be readily perceived that bythe acvtion of the lever beam (F), having its fulcrum on the rock shafty (G), its extreme end to which is attached the rocking link (it) will describe the arc of a circle, and consequently in rising, las said end gradually ap-A swings on a wrist in the middle of the crossproaches the horizontal plane of its axis or l fulcrum, it will gradually extend the lower end of said rock-ing link, beyond the vertical line of its axis, and ca'usethe upper end which is attached to the saw, to recede within said vertical line, thus drawing the saw, away from its work in a line very nearly the angle of the back'of the tooth, which is best adapted to free it from gum or other substance which may have accumulated p thereon, and in' its downward action the saw will be caused to advance graduallyand regularly to its work. It is obvious that,

were the sliding ro-cking link -dispensed with, and the lever beam (F) made to form a direct connection with the saw, a much' less gradual receding action would be given to the saw and a less effective lone also as, to get the necessary stro-ke to the saw with the same length of lever beam (and to make it longer would be objectionable as regards the portability, et cetera, of the machine), the saw would then necessarily be caused to recede more rapidly and further than requisite for mere clearance from gum and saw dust and in aline or direction not corresponding to the back run ofthe teeth consequently not so well calculated to cause the teeth to V clear themselves; while, in the downward action of the saw, the effect would be equally as objectionable'on account of the abruptness and irregularity given'to the advance movement of the saw, and, if the lever beaml were worked by crank below the horizontal position, the saw would then be made to advance rapidly into the wood during the early part of the downstroke and recede,or

advance but slowly and slightly, at the close of the same stroke, thereby producing much irregularity in the power requisite to drive the saw, as well as being in other respects objectionable. The gradual and uniform action given both in receding and advancing by the arrangement herein specified, of the sliding rocking link with the lever beam and saw, insures all clearance from gum and sawdust, an easy cut, and regularity in the power requisite to drive the same. The weight of the lever or half beam (F) is thrown entirely on the saw, to assist it in its cut, and acts as a counter balance in its upward motion, and `thus economizes and equalizes the work upon the propelling power. The motion is communicated to this lever by a Vcrank (i) on the main shaft through the pitman (1); and on the end of saidshaft, outside of the main frame (A) is hung a flywheel (J), from which, when used as avport'able mill, projects a wrist or crank pin for the `pitman of a steam engine, which may be of any of the well known varieties, therefore any further description of it here would be superfluous; but when this mill is used in connection with other machinery, and a distinct propelling power is not required, any other power may be communicated, through a. band wheel on said main shaft, in place of or in front of the fly wheel. The feed motion is communicated to the carriage, through a pinion (7n) on the counter shaft (Z), gearing into a rack on the under side of the carriage (B), in the ordinary mannei'. On the end of this shaft and outside of the main frame, is a ratchet whe-el, which is moved to feed up the log, (it being secured in the ordinary way with head and tail blocks4 (m, m,) on the carriage,) during the upward motion of the saw, by the iin* ger (a) 'attached to and operated by the elbow lever (L) on the end of the rock shaft (Gr). This finger is suspended by a line to one end of a balance lever over head,

having its fulcrum about overthe center of the carriage, its other end extending across tothe opposite side of the mill, where 1s attached to it a rod (s) reaching down to,` the main frame and resting thereon, which is sufiiciently heavy to bear up the linger holding it out of gear of the ratchet wheel, when tripped by the projection (0) on the side of the carriage for that purpose. There is also on this counter shaft a spur wheel (p), gearing into a pinion (g), which is loose o-n the main shaft (H) and can be clutched through the lever (fr) at the `will of the attendant to run or gig the carriage back, preparatory to making another out; beneath the main frame at either end, are axles (t) so that the entire mill wit-h steam engine attached, in regular working order and readyfor use, can be mounted on wheels and transported from placeto place at pleasure.

Having thus fully described my invention what I claim therein as new and desire to secure by Letters Patent, is*

1. The method herein described of communicating the advance and receding motion to the saw as and for the purposes set forth.

2. l further claim the combination and arrangement of the half beam lever (F) and rocking link (it) with the saw, when operated by a crank or its equivalent, and pitman, connected at any point between the fulcrum of said leverand the saw.

In testimony whereof, I have hereunto subscribed my name this 29th day of Novr., 1853.

l FREDK. T. ANDREWS.`

` Vitnesses:

' SAML. GRUBB,

WM. M. SMITH. 

